G++ not removing static class instance

Asked Jun 28 '18 at 13:44

Active Jun 28 '18 at 13:44

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toolchain : arm-none-eabi-gcc/g++ 7.3.1 (june 2018)

target : Cortex M4

C++ flags :

-D${CPU_NAME}  -mcpu=${CPU} -mthumb -mfloat-abi=hard -mfpu=${FPU} \
    -Wfatal-errors -Wall -Wno-unused-function \
    -fdata-sections -ffunction-sections \
    -fno-exceptions -fno-non-call-exceptions -fno-rtti -fno-use-cxa-atexit

Linker flags

--specs=nano.specs -Wl,--gc-sections -Wl,--strip-all --verbose \
    -Wl,-Map=${OUTPUT_FILE_NAME}.map -T\"${LINKER_FILE}\"

Unused variables are optimized away thanks to -fdata-sections -ffunction-sections and -Wl,--gc-sections

Why is an unused static class instance not optimized away ? Am I missing on option ?

asked Jun 28 '18 at 13:44

Julien

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Possible side effects in constructor/destructor which should be visible (auto registration, ...). – Jarod42 Jun 28 '18 at 13:45
Please, provide [MCVE](https://stackoverflow.com/help/mcve). – Dan M. Jun 28 '18 at 13:51
In substance I found the answer is already here: https://stackoverflow.com/questions/5302848/g-does-not-show-a-unused-warning – Julien Jun 28 '18 at 13:52
Then you might want to answer your own question. – Adrian W Jun 28 '18 at 13:57
Or mark it as a duplicate. – n. m. could be an AI Jun 28 '18 at 13:58

G++ not removing static class instance

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